1. The purchases were made in accordance with Rule 10b-18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act").

2. The shares reported as purchased on June 27, 2018 were purchased in multiple transactions at actual purchase prices ranging from $12.40 to $12.60 per share and the shares reported as purchased on June 28, 2018 were purchased in multiple transactions at actual purchase prices ranging from $12.22 to $12.76 per share, in each case exclusive of any fees, commissions or other expenses. The price reported reflects the weighted average purchase price for the transactions. The Reporting Persons undertake to provide, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer, full information regarding the number of shares purchased at each separate price.

3. These securities are directly held by Invus Public Equities, L.P.

4. These securities are directly held by Artal International S.C.A.

5. These securities are directly held by Invus, L.P.

6. Invus Public Equities Advisors, LLC is the general partner of Invus Public Equities, L.P., and Invus Advisors, L.L.C. is the general partner of Invus, L.P. Artal International S.C.A. is the managing member of each of Invus Public Equities Advisors, LLC and Invus Advisors, L.L.C. The managing partner of Artal International S.C.A. is Artal International Management S.A., both of which are wholly owned subsidiaries of Artal Group S.A., which is a wholly owned subsidiary of Westend S.A., which is a wholly owned subsidiary of Stichting Administratiekantoor Westend (the "Stichting"). Mr. Pascal Minne is the sole member of the board of the Stichting.

7. Each of the Reporting Persons (other than to the extent it directly holds securities reported herein) disclaims beneficial ownership of the securities held by the other Reporting Persons, except to the extent of such Reporting Person's pecuniary interest therein, and, pursuant to Rule 16a-1(a)(4) under the Exchange Act, each of the Reporting Persons (other than to the extent it directly holds securities reported herein) states that the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of all of the reported securities for purposes of Section 16 of the Exchange Act or for any other purpose.

Remarks:

Invus C.V. directly holds 4,321,214 shares of Issuer common stock. None of the Reporting Persons listed in Footnote 6 hereof have any beneficial or pecuniary interest for purposes of Section 16 of the Exchange Act in the shares of Issuer common stock directly held by Invus C.V. For purposes of Section 16 of the Exchange Act, the Reporting Persons may be deemed to be directors by deputization of the Issuer by virtue of Invus, L.P.'s right to designate certain members of the Issuer's board of directors pursuant to a stockholders' agreement between the Issuer and Invus, L.P.

See Signatures Included in Exhibit 99.1

06/29/2018

** Signature of Reporting Person

Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person,
see
Instruction
4
(b)(v).